a. Field of the Invention
This invention relates to vehicle brakes. In particular, the invention relates to a bracket assembly for mounting a brake assembly and a brake actuator that is better able to withstand mechanical stress within the bracket assembly as compared to conventional bracket assemblies yet is easier to manufacture than conventional bracket assemblies.
b. Background Art
In a conventional drum brake, a brake drum rotates with a wheel or wheels proximate to one end of an axle. The drum defines a radially inner braking surface. A brake spider is disposed about the axle and a pair of brake shoes are pivotally mounted at one end to the brake spider. The opposite end of each brake shoe is engaged by an actuating member such as a cam to move the brake shoes between positions of engagement and disengagement with the braking surface of the brake drum. The cam is driven by a brake actuator acting on one end of a camshaft supporting the cam.
Referring to FIGS. 1-2, in one conventional drum brake, a bracket assembly 10 supports various components of a brake assembly 12 and a brake actuator 14 and positions them relative to one another. The bracket assembly 10 includes a tube 16 through which the camshaft 18 extends and a mounting arm 20 and mounting flange 22 welded to either end of the tube 16 and configured for coupling to the brake actuator 14 and a brake spider 24, respectively. A support 26 is often installed between the vehicle axle 28 and the tube 16 and a gusset 30 is often installed between the tube 16 and arm 20 in order to reduce stress on welds within assembly 10 and to reinforce arm 20.
The above-described design for the bracket assembly 10 has several drawbacks. The mounting arm 20 supporting the brake actuator 14 must be relatively thick to withstand the loads generated by actuation and vibration of the brake actuator 14. The thickness of the arm 20 requires heavy tooling in order to manufacture the arm 20 and prevents formation of intricate features on the arm 20. The gusset 30 used to reinforce the arm 20 provides support to one only end of the arm 20 and requires two additional welds—one weld between one end of the gusset 30 and the tube 16 and another weld between the opposite end of the gusset 30 and the arm 20. Further, even with the addition of the gusset 30, bending and torsional loads cause significant mechanical stress in the welds and significant structural deflection that results in increased air consumption during braking.
The inventor herein has recognized a need for a bracket assembly for mounting a brake assembly and a brake actuator that will minimize and/or eliminate one or more of the above-identified deficiencies.